.,-n_n— -r\, 


REESE  LIBRARY 


UNIVERSITY  OF  CALIFORNIA. 


Class 


I 


ENGINEERING 
STUDIES 


PART  I 

AMERICAN  STONE  ARCHES 


BY  CHARLES    EVAN    FOWLER,  M.  AM.  S< 


* 


(p— iv_n- 


REESE  LIBRARY 

:  Ml- 

UNIVERSITY  OF  CALIFORNIA. 


Accession  No.        83125.    Cla^  N 


— i,ne  j^  correct  span  is 


ENGINEERING 
STUDIES 


PART  I 

AMERICAN  STONE  ARCHES 


BY  CHARLES    EVAN    FOWLER,  M.  AM.  Soc.  C.  E. 

11 


'Whoever  thinks  a  Faultless  piece  to  see, 

Thinks  what  ne'er  was,  nor  is,  nor  e'er  shall  be." 

********* 

'Content  if  hence  th'  unlearn'd  their  wants  may  view, 
The  learn'd  reflect  on  what  before  they  knew." 

— Pope. 


FIRST    EDITION. 
NEW  YORK. 

THE    EXCINEERING    NEWS    PUBLISHING    CO. 

1899. 


Copyright,  1M«.«»,  by 
CHARLES   EVAN   FOWL.KK. 


10 


ENGINEERING     STUDIES. 

INTRODUCTION. 

This  collection  of  photographic  views  of  Engineering  Works 
should  be  found  valuable  alike  to  the  practicing  engineer  and  to  the 
student. 

Short  descriptions  and  criticisms  are  appended  to  point  cut  the  good  and 
the  bad  features  of  the  designs,  with  the  view  of  bettering  the  character 
of  future  engineering  structures.  A  stone  arch  is  very  often  regarded  as 
a  work  of  art  so  aesthetic,  that  it  cannot  be  injured  in  appearance  by  care- 
less detailing.  Never  was  there  a  greater  mistake  than  this,  nor  one  more 
frequently  made. 

The  intention  is  to  bring  out  a  number  of  parts  forming  a  series  which 
will  include,  in  addition  to  stone  arches,  Bridge  Approaches  of  Masonry, 
Bridge  Towers  and  Portals,  Notable  Bridge  Piers,  Tunnel  Portals  and 
other  engineering  works  of  like  character. 

There  will  be  six  parts  devoted  to  stone  arches  of  several  countries, 
and  six  or  more  parts  devoted  to  miscellaneous  structures. 


AMERICAN  STONE  ARCHES., 

UNIVERSF 


THE  CABIN  JOHN  ARCH. 

THE  largest    stone   arch   ever   built  was  the  one   constructed  over  the 
river  Adda  at  Trezzo,  by  order  of  the  Duke  of  Milan,  about  the  year 
1380.     It   had  a  span  of  251  feet  at  low  water,  but  it  was  destroyed 
in  1427,  and  now  only  about  24  feet  of  the  arch  ring,  near  each  haunch,  re- 
mains. 

The  largest  one  in  existence  at  the  present  time,  is  the  Cabin  John 
bridge  and  aqueduct  over  Rock  Creek,  at  Washington,  D.  C.  It  was  de- 
signed by  Gen.  M.  C.  Meigs,  and  has  a  span  of  220  feet,  a  rise  of  57  feet, 
while  the  roadway  of  20  feet  width  is  101  feet  above  the  stream.  The 
arch  ring  is  of  granite,  six  feet  deep  at  the  -Grown  and  four  feet  at  the  cen- 
ter; the  spandrels  are  of  sandstone,  laid  partially  with  radial  joints.  The 
splendid  architectural  effect  is  due  to  the  proportions  and  to  the  relief  af- 
forded by  the  projecting  courses  at  the  roadway,  which  gives  a  cornice-like 
effect  in  entire  harmony  with  the  whole  design.  This  can  best  be  expressed 
by  quoting  from  what  Fergusson  has  to  say  in  his  "History  of  Architecture,'" 
regarding  the  efforts  of  the  engineer  at  architectural  effects. 

"If  this  is  all  that  can  be  done  with  bridges,  (their  decoration  with  inap- 
propriate details)  it  is  far  better  that  they  should  be  left,  like  most  of  those 
recently  built,  to  tell  their  own  tale  without  any  ornament  whatever.  A  long 
series  of  tall  arches  is  so  beautiful  an  object  in  itself  that  it  is  difficult  to 
injure  it;  but  occasionally  a  slight  moulding  at  the  impost,  a  bold  accen- 
tuation of  the  arch,  and  bold  marking  of  the  roadway  render  those  beauti- 
ful which  otherwise  may  only  be  useful  in  appearance." 

11 


THE   WHEELING   STONE  ARCH. 

THE  Wheeling  stone  arch  bridge  is  one  of  the  largest  stone  arches 
in  the  United  States,  having  a  span  of  159  feet.  The  intrados  is  the 
arc  of  a  circle,  with  a  rise  of  twenty-eight  feet.  The  depth  of  key- 
stone is  4'  6".  Longitudinal  arched  voids  are  employed  underneath  the 
roadway. 

The  engineers  of  the  work  were  Hoge  &  White,  the  bridge  being  com- 
pleted in  1893.  The  large  span  marks  the  structure  as  a  notable  piece  of 
engineering  work,  and  the  detail  of  the  parapet  is  very  pleasing  in  appear- 
ance, although  very  simple  in  design.  The  coping  with  the  supporting 
corbels  is  also  very  effective.  Berea  stone  was  used  for  most  of  the  work, 
which  amounted  to  about  9,000  yards,  there  being  6,000  yards  of  dimen- 
sion stone.  The  cost  of  the  bridge  was  $130,000. 

The  meeting  of  two  straight  grades  at  the  center  of  the  span  is  hardly 
the  best  solution  possible  for  giving  increased  waterway,  although  plenty  of 
precedent  can  be  found  for  such  an  outline.  A  much  more  pleasing  method 
would  have  been  to  use  a  parabolic  curve  for  the  longitudinal  profile  of  the 
roadway  and  coping. 

Had  the  offset  in  the  retaining  wall  been  made  at  the  springing  of  the 
arch,  as  a  division  between  the  spandrel  and  retaining  walls,  it  would  have 
been  more  logical  and  the  effectiveness  of  the  structure  as  an -architectural 
work  much  heightened. 


HARTFORD  MEMORIAL  BRIDGE  AND  ARCH. 

ONE  of  the  handsomest  stone  arch  bridges  in  the  United  States  is  the 
brownstone  structure  in  Bushnell  Park,  at  Hartford,  Conn.  Its 
effectiveness  is  largely  due  to  the  Memorial  Arch,  over  the  drive- 
way leading  up  to  the  Capitol  building. 

The  bridge  was  constructed  originally  in  1850,  of  Portland  brownstone, 
and  at  a  cost  of  about  $15,000.  Of  the  five  arches,  each  having  a  span  of 
twenty-five  feet,  the  three  center  ones  are  semi-circular,  while  the  two  end 
ones  are  three  center,  with  radii  of  8l/2  feet  and  14^  feet.  The  original 
width  of  the  bridge  was  thirty-five  feet,  but  in  1885  it  was  rebuilt  to  match 
the  Memorial  Arch,  and  the  width  increased  to  forty-one  feet  extreme,  or 
with  a  roadway  of  twenty-eight  feet  and  two  sidewalks  of  four  feet  each. 
The  widening  was  accomplished  by  tearing  down  the  spandrel-walls  to  the 
top  of  the  arch  rings  and  supporting  the  added  width  by  elegant  stone 
brackets,  adding  much  to  the  beauty  of  the  bridge;  while  the  design  was 
made  to  harmonize  with  the  Memorial  by  a  parapet  railing  of  elegant 
design. 

The  remodeling  of  the  bridge  cost  $11,287,  while  the  cost  of  the  Soldiers' 
Memorial  was  $60,000.  This  was  executed  in  brownstone  and  terra  cotta, 
from  the  designs  of  Mr.  Geo.  Keller,  a  prominent  Hartford  architect.  The 
two  structures,  when  considered  as  a  whole,  form  one  of  the  most  notable 
of  monumental  works. 


THE    ELYRIA    ARCHES. 

THE  streams  at  Elyria,  Ohio,  have  solid  rock  banks  and  beds,  and  the 
skevvbacks  for  the  eastern  and  western  stone  arches  are  cut  in  the 
solid  rock  of  the  banks.  The  situations  are  very  picturesque  and  the 
falls  below  the  western  bridge,  forty  feet  high,  add  much  to  the  view. 

The  eastern  arch  is  the  third  largest  stone  span  in  the  United  States  and 
was  constructed  from  the  plans  of  E.  C.  Kinney  in  1886;  the  span  being  150 
feet,  the  rise  24  feet,  the  width  over  all  32  feet,  while  the  depth  of  the  arch 
ring  at  the  springing  is  4  feet  6  inches  and  at  the  keystone  3  feet  9  inches. 
In  the  view  of  this  arch,  a  beautiful  two-span  stone  bridge  on  the  Lake  Shore 
Railway  can  be  seen  in  the  background. 

The  western  arch  was  designed  by  E.  S.  Jackson  and  E.  M.  Bunce  and 
was  built  in  1894.  This  span  is  the  fifth  largest  in  the  United  States,  having 
a  span  of  112  feet,  a  rise  of  19  feet  6  inches,  a  width  across  the  arch  ring  of 
38  feet,  and  a  width  on  top  of  44  feet.  The  skewbacks  are  from  4  to  8  feet 
above  the  bed  of  the  stream,  the,  arch  ring  having  a  depth  at  the  keystone  of 
3  feet  6  inches. 

Both  arches  are  constructed  with  first-class  rock-faced  masonry,  the  stone 
being  Elyria  sandstone,  quarried  in  the  vicinity.  The  width  of  both  arches 
has  been  increased  by  projecting  corbel  courses  and  coping,  which  only  serve 
to  intensify  the  shallow  depth  at  the  center.  Had  separate  corbels  been  sub- 
stituted for  the  corbel  course  on  the  large  span,  and  for  the  lower  corbel 
course  on  the  small  one,  giving  the  effect  of  dentils,  the  appearance  at  the 
center  would  have  been  much  improved.  A  stone  parapet  would  have  been 
a  still  further  improvement  in  this  respect. 

While  having  the  graceful  architectural  appearance  one  would  expect  in 
arches  of  such  bold  outline,  they  are  nevertheless  somewhat  severe  in  design. 
This  effect  has  been  lessened  somewhat  by  the  addition  of  the  consoles  on 
the  eastern  arch,  which  also  afford  retreats  on  the  sidewalks. 


THE  SCHENtEY   PARK   ARCH. 

THE  stone  arch  bridge  recently  completed  in  Schenley  Park  at  Pitts- 
burg  is  known  as  the  Bellefield  Bridge.     It  was  designed  by  H.  B. 
Rust,  Engineer  of  Schenley  Park,  and  is  one  of  the  most  elaborate 
stone  bridges  in  this  country.^  ^ 

It  has  a  span  of  136'  feet  7  inches  and  a  width  across  the  soffit  of  82 
feet.  The  roadway  is  60  feet  in  width,  while  the  two  sidewalks  have  a  width 
of  ten  feet  each.  The  depth  of  keystone  is  four  feet. 

The  arch  is  a  very  bold  one,  and  the  general  design  leaves  little  to  be 
desired,  while  the  balustrade  is  a  most  elegant  piece  of  work.  It  is,  how- 
ever, unfortunate  that  the  abutments  and  the  spandrels  were  decorated  with 
the  paneling,  as  the  apparent  size  of  the  arch  is  very  much  reduced  by  these 
details  which  have  been  characterized  by  Fergusson  in  a  criticism  of  the 
Chester  bridge  as  a  mistaken  application. —  "by  exaggerating  his  details, 
the  bridge  has  been  dwarfed  in  exactly  the  same  manner  as  the  basilica." 
('It  is  far  better  that  we  should  be  content  with  plain,  honest,  solid 
but  useful  erections,  than  that  our  buildings  should  be  adorned  on  the  mis- 
taken principles  which  have  hitherto  been  supposed  to  constitute  the  Art  of 

Architecture." 

13 


HIGH    BRIDGE,   CROTON   AQUEDUCT. 

THE  most  notable  stone  bridge  in  the  United  States,  not  on  account  of 
the  size  of  the  spans,  but  because  of  its  height,  chaste  design  and  mon- 
umental   character,    is    the   structure  which  carries  the  Croton  Aque- 
duct over  the  Harlem  River  at  New  York  City,  from  the  mainland  to  Manhat- 
tan Island.    The  erection  of  the  remarkable  Washington  Bridge,  close  to  it, 
with  its  great  steel  spans,  instead  of  detracting  from  its  appearance  as  might 
be  expected  has  only  enhanced  it. 

The  original  intention  was  to  carry  the  water  across  the  river  by  a 
siphon  pipe  line  through  a  tunnel,  and,  while  the  estimated  cost  was  much 
less  than  for  a  high  bridge,  the  uncertainties  were  so  great  as  to  cause  its 
abandonment. 

The  location  is  a  very  beautiful  one,  the  south  shore  being  an  abrupt 
bluff  of  solid  gneiss  rock,  crowned  with  trees. 

The  requirements  of  navigation  made  it  necessary  to  have  a  clear  height 
of  100  feet  above  the  river,  and  openings  of  80  feet  in  width.  The  top  of  the 
parapet  is  116  feet  above  high  water,  while  there  are  eight  semicircular 
arches  of  80  feet  each  over  the  river,  one  arch  of  50  feet  in  the  Manhattan  ap- 
proach and  six  arches  of  50  feet  span  in  the  opposite  one. 

The  river  is  620  feet  in  width  at  ordinary  high  water,  the  distance  up 
to  the  springing  of  the  arches  being  60  feet,  or  95  feet  above  the  lowest 
foundation.  The  total  length  of  the  bridge  is  1,460  feet,  and  it  originally  car- 
ried two  cast-iron  pipes,  3  feet  in  diameter,  to  convey  the  water,  their  use 
being  with  the  object  of  preventing  leakage,  which  would  eventually  injure 
tne  bridge.  When  it  was  desired  to  increase  the  carrying  capacity  a  third 
pipe,  7  feet  6  inches  in  diameter,  was  added. 

The  structure  was  designed  under  John  B.  Jervis,  Chief  Engineer  of 
the  Croton  Aqueduct,  and  was  let  at  a  contract  price  of  $737,755.  It  occu- 
pied five  years  in  building,  being  completed  in  1842. 

The  arch  ring  is  finely  accentuated,  but,  unfortunately,  the  tailing  of  the 
ring  stones  does  not  match  with  the  courses  in  the  spandrels.  The  piers, 
spandrels  and  parapets  have  a  batter  of  I  in  48,  the  width  across  on  top  of 
ihe  parapets  being  21  feet.  The  length  of  the  piers  is  greater  than  the 
width  of  the  arches,  and  counterforts  are  carried  up  with  good  effect.  The 
belt  course  directly  above  the  voussoirs  is  in  entire  harmony  with  the  cor- 
nice above,  which  is  formed  by  ornamental  corbels  supporting  the  coping, 
thus  making  a  portion  of  the  footways  on  each  side. 

The  footways  are  protected  by  iron  railings  of  light  design,  which,  how- 
ever, appear  well,  owing  to  the  great  depth  of  masonry  above  the  extrados. 
The  difference  in  the  height  of  the  springing  of  the  50  feet  spans  and  the  80 
feet  spans  is  taken  care  of  in  a  very  appropriate  manner  by  the  two  coping 
courses  on  the  piers  which  are  common  to  both. 

The  water  tower  of  elegant  design  adds  much  to  the  architectural  ef- 
fect, which  is  not  much  marred  by  the  well-designed  stack.  While  many 
European  structures  are  more  expensive  and  more  elaborate,  High  Bridge 
compares  favorably  with  them,  and  will  remain  for  scores  of  years,  a 
credit  not  alone  to  the  engineer  who  conceived  it,  but  to  the  City  of  New 
York  as  well. 

14 


THE   WISSAHICKON   ARCH,   PHILADELPHIA. 

THE  bridge  in  Fairmount  Park,  Philadelphia,  over  Wissahickon  Creek 
is  a  very  handsome  structure,  having  been  built  from  the  design  of 
General  Russell  Thayer,  chief  engineer  of  The  Fairmount  Park 
Commission,  at  a  cost  of  $27,743,  including  the  removal  of  the  old  bridge. 

The  arch  is  on  a  skew  of  69  degrees  26  minutes,  which  is  taken  up  by 
arch  rings,  four  feet  wide  each.  The  span  of  each  ring  is  106  feet  6  inches, 
the  clear  span  of  the  arch  105  feet  and  the  rise  11  feet.  The  spring  of  the 
arch  is  about  six  feet  above  the  surface,  at  which  point  thearch  ring  has  a 
depth  of  4  feet  6  inches,  while  the  depth  of  keystone  is  3  feet. 

The  roadway  25  feet  in  width  and  the  two  sidewalks  of  5  feet  width 
each  are  paved  with  asphalt. 

The  stone  of  which  the  arch  was  built  was  quarried  about  one-half  mile 
from  the  site  and  is  a  dark  colored  gneiss.  The  stone  work  is  quarry- faced 
ashlar,  with  a  one-inch  chisel  draft  at  each  joint,  thus  making  a  two-inch 
draft  at  each  joint.  This  gives  a  very  fine  appearance  to  the  work. 

The  shallow  depth  at  the  center  is  relieved  by  the  solid  parapet,  which 
has  dressed  stone  coping,  post  and  caps,  and  which  is  supported  on  a  cop- 
ing, carried  by  well  proportioned  modillions. 

The  symmetry  of  the  design  is  unfortunately  spoiled  by  the  character 
of  the  bank  at  the  left  end,  which  is  the  more  to  be  regretted  as  the  right 
abutment  is  a  most  suitable  and  elegant  arrangement. 


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ENGINEERING 
STUDIES 


PART  II 

OMAN  STONE   ARCHES 


"Wh< 

hence  th' 
The  learn'd  reflect  on  w! 


WS  PUBLISH 


1900. 


ENGINEERING 
STUDIES 


PART  II 

ROMAN   STONE   ARCHES 


BY  CHARLES  EVAN   FOWLER,  M.  AM.  Soc.   C  E. 


OF   THK 

|  UNIVERSITY  ) 


"Whoever  thinks  a  Faultless  piece  to  see, 
Thinks  what  ne'er  was,  nor  is,  nor  e'er  shall  be." 

*  *  *  #  *  *  #  -|:  * 

"Content  if  hence  th'  unlearn'd  their  wants  may  view, 
The  learn'd  reflect  on  what  hefore  they  knew." 

— Pope. 


FIRST  EDITION. 
NEW  YORK. 

THE   ENGINEERING   NEWS   PUBLISHING   CO. 

1900. 


Copyright,  1900,  by 
CHARLES  EVAN  FOWLER. 


10 


THE  OLD  ROMAN  AQUEDUCTS, 

THERE  are  no  more  striking  examples  of  the  grandeur  of  simplicity 
in  the  design  of  stone  bridges  than  the  old  Roman  aqueducts.  The 
long  lines  of  arches  still  standing  on  the  otherwise  deserted  plains  of 
the  Campagna,  are  examples  likewise  of  the  splendid  character  of  the 
workmanship  of  the  Romans,  who  apparently  built  their  engineering  struc- 
tures to  last  for  all  time. 

The  rectangular  stone  piers  were  capped  with  simple  stone  copings,  the 
full  semi-circular  arches  sprang  directly  from  these,  while  the  depth  above 
the  arch  ring  necessitated  for  the  conduits,  ornamented,  hy  simple  belt 
courses  and  surmounted  by  a  coping  and  a  triangular  capping  gave  the 
structure  a  dignity  which  even  in  the  ruined  condition  of  the  present  time 
has  not  been  lost. 

The  engineering  skill  displayed  in  their  design  was  remarkable,  show- 
ing that  the  Romans  were  well  informed  in  scientific  matters.  The  conduits 
have  uniform  grades  for  long  distances,  having  been  apparently  constructed 
from  precise  levels  of  the  country  over  which  they  were  built. 

The  stone  of  which  they  were  constructed  was  carefully  squared  and 
in  some  instances  different  colored  stone  was  employed  for  architectural 
effect.  Most  of  the  work  was  done  upon  them  during  the  winter  season, 
as  the  masonry  was  thought  to  dry  out  too  quickly  if  laid  in  the  summer. 
There  were  nine  aqueducts  used  to  supply  the  city  of  Rome  with  water  in 
the  time  of  Frontinus,  the  Aqua  Appia,  Anio  Vetus,  Aqua  Marcia,  Aqua 
Tepula,  Aqua  Julia,  Aqua  Virgo,  Aqua  Alsietina,  Aqua  Claudia,  and  the 
Anio  Novus. 

Of  these  the  Aqua  Claudia  was  the  most  remarkable  for  its  construc- 
tion and  arrangement,  having  a  length  of  nearly  fifty  miles  and  carrying 
water  from  two  streams  above  Tivoli.  Nearly  one-third  of  its  length  was 
carried  on  arches. 

BRIDGE  OF  SANT'  ANGELO. 

THE  bridge  of  Sant'  Angelo,  was  originally  called  the Pons  a  Elius, being 
at  the  time  of  its  construction  the  seventh  bridge  over  the  Tiber. 
The  river  being  only  about  300  feet  wide  on  the  average  on  this 
portion.  It  was  constructed  under  Hadrian,  A.  D.,  138,  being  opposite  the 
tomb  of  Hadrian,  which  is  now  known  as  the  Castle  of  Sant'  Angelo. 

The  piers  were  surmounted  by  colossal  bronze  statues  and  columns, 
which  were  destroyed  during  troubles  in  Italy.  The  width  of  the  bridge  is 
50  feet  9  inches,  while  the  small  spans  are  26  feet  3  inches,  and  the  large 
spans  62  feet  4  inches.  The  statues  were  replaced  by  Pope  Clement  IX.  in 
1668,  by  colossal  statues  of  angels  on  pedestals  of  white  marble,  from 
Bernini's  original  design.  While  such  decoration  is  entirely  out  of  place 
in  bridge  construction,  it  does  not  mar  the  effect  of  such  a  structure  in  Rome, 
where  everything  is  of  a  monumental  character,  as  it  might  elsewhere. 

The  molded  archivolt,  while  a  somewhat  trivial  detail  for  a  bridge,  really 
adds  to  the  appearance  of  arches  having  such  small  spans. 

11 


BRIDGE  OF  AUGUSTUS   AT   RIMINI. 

THE  most  copied,  probably,  of  old  Roman  bridges  is  the  one 
built  by  the  Emperor  Augustus  at  Rimini.  There  are  five 
semi-circular  arches,  which  was  the  universal  Roman  out- 
line, the  two  spans  next  to  the  shore  on  either  side  being  of  twenty- 
three  feet  five  inches  span,  and  the  three  intermediate  spans  of  twenty- 
eight  feet  nine  inches  span. 

The  piers  are  very  thick,  being  nearly  equal  to  half  the  opening, 
and  rise  thirteen  feet  one  inch  above  the  water,  carrying  columns 
which  support  an  entablature.  The  remains  of  decorations  on  the 
keystones,  the  ruined  cornice  and  other  details,  indicate  that  the 
bridge  was  one  of  great  elegance. 

That  some  of  the  design  should  have  been  duplicated  in  other  struc- 
tures was  indeed  fortunate,  but  that  the  columns  and  entablatures 
were  added  to  bridges  of  later  design,  points  to  this  as  an  unfor- 
tunate field  of  study  for  modern  engineers.  This  detail  could  be 
replaced  by  counterforts  which  would  be  appropriate  and  harmonious 
as  well. 


BRIDGE  OF  ALCANTARA 

LESS  is  known  about  the  architecture  and  engineering  of  Spain  than 
of  any  of  the  other  European  countries.     There  are  many  interest- 
ing bridges  at  various  points,  but  the  most  famous  ones  are  those  at 
Toledo.     The  oldest  one  was  constructed  by  the  Emperor  Trajan  and  was  a 
marvel  of  engineering.     The  one  illustrated  was  constructed  in  the  year 
997.     The  general  style  of  the  structure  is  Roman — bold  circular  arches,  of 
which  the  larger  one  has  a  span  of  ninety-three  feet. 

The  starling  of  triangular  section,  supports  a  counterfort,  which  afforded 
opportunity  for  constructing  a  retreat.  A  second  retreat  is  cantilevered  out 
over  the  right  abutment,  and  while  it  is  a  pleasing  detail,  the  patched  con- 
dition of  the  wall  destroys  the  effectiveness  of  this  and  the  small  Moorish 
arch,  which  is  placed  in  a  location  which  is  unaccountable.  The  tower 
at  the  left  and  the  arched  portal  at  right  end  of  the  roadway  contribute  to 
make  it  a  striking  piece  of  bridge  architecture,  notwithstanding  the  lack  of 
harmony  which  has  resulted  from  the  various  additions  which  have  been 
made.  The  portal  at  the  left  is  of  Moorish  origin  and  is  a  very  notable 
example  of  this  feature  of  bridge  design. 


12 


THE  BRIDGE  OF  THE  RIALTO. 

THE  city  of  Venice  is  built  upon  two  islands,  which  are  separated  by  a 
serpentine  waterway,  known  as  the  Grand  Canal,  across  which  is 
built  the  bridge  of  the  Rialto.  The  name  Rialto  is  derived  from  the 
original  name  of  the  island  first  settled — Ripa  Alta. 

The  foundations  of  all  the  structures  were  made  with  great  care,  re- 
quiring the  use  of  masses  of  concrete  or  the  driving  of  piles. 

The  bridge  of  the  Rialto  was  constructed  from  the  design  of  Michael 
Angelo,  in  1578.  As  is  well  known,  the  painters  of  this  period  were  also 
architects  of  recognized  ability  and  applied  this  knowledge  to  the  design  of 
engineering  works  as  well,  with  the  result  that  such  structures  partake  very 
largely  of  the  character  of  works  of  architecture,  being  decorated  with  its 
conventional  details. 

The  span  of  this  arch  is  96  feet  10  inches  and  the  rise  20  feet  7  inches. 
The  arch  ring  is  handsomely  molded,  while  the  spandrels,  the  masonry  of 
which  is  laid  with  radial  joints,  are  decorated  with  figures  of  angels  in 
relief  and  tablets  bearing  inscriptions.  At  either  end  are  niches  of  beau- 
tiful design,  forming  places  for  other  figures. 

The  bridge  carries  two  rows  of  shops,  formed  by  arcades,  between 
which  is  a  passage.  The  principal  footways  on  the  outside  are  supported 
by  corbels,  an  arrangement  which  causes  the  depth  at  the  center  to  appear 
more  shallow  than  it  is  in  reality — on  account  of  the  great  overhang. 

The  footways  are  protected  by  balustrades  of  beautiful  design,  and  on 
account  of  the  ascent  being  steep  marble  steps  are  provided. 

The  arcades  are  quite  a  study  in  themselves,  the  large  central  arches 
forming  a  cross  passage.  The  six  arches  on  either  hand  springing  at  dif- 
ferent levels,  present  a  remarkably  good  solution  of  this  difficult  problem 
in  design.  The  lack  of  a  thick  abutment  at  each  end  and  the  shallow 
depth  over  the  haunches  of  the  large  arches  are  faults  which  are  to  a  great 
extent  lost  sight  of,  owing  to  the  striking  character  of  the  entire  bridge. 


OF  THE 

UNIVERSITY 


THE   PONT   DU   CARD,   NIMES,   FRANCE. 


THE  Pont  du  Card  was  among  the  first  of  the  great  Roman  en- 
gineering works  to  be  built  in  the  countries  conquered  by 
them,  and  was  probably  constructed  by  Agrippa,  the  gov- 
ernor at  Nimes,  France,  under  the  great  Augustus,  about  the  begin- 
ning of  the  Christian  era,  and  is  still  in  good  condition,  due  to  the 
perfect  and  solid  construction  and  to  repairs  which  have  been  made 
from  time  to  time.     Hamlin  in  his  "History  of  Architecture,"  says 
"these  Roman  works  of  utility  were  in  many  cases  designed  with  an 
artistic  sense  of  proportion  and  form  which  raises    them    into    the 
domain  of  genuine  art.    A  remarkable  effect  of  grandeur  was  often 


13 


produced  by  the  form  and  proportions  of  the  arches  and  piers,  and  an 
appropriate  use  of  rough  and  dressed  masonry.  They  are  impressive 
rather  by  their  length,  scale,  and  simplicity,  than  by  any  special  re- 
finements of  design." 

The  structure  illustrated  was  a  part  of  a  great  aqueduct  system.  It 
has  a  height  of  161  feet  from  the  bed  of  the  river,  a  length  at  the  top 
of  the  first  story  of  562  feet,  and  at  the  top  of  the  second  story  of  885 
feet. 

The  large  arch,  through  which  the  river  Garden  runs,  is  80  feet  5 
inches,  the  other  large  arches  from  51  to  63  feet  span,  while  the  small 
arches  of  the  upper  story  are  15  feet  9  inches.  The  original  width  at 
the  top  of  the  first  story  was  20  feet  9  inches,  while  the  second  is  15 
feet  and  the  third  1 1  feet  9  inches.  There  is  now  room  on  the  first 
story  to  allow  for  travel  across  the  valley. 

The  foundations  are  built  on  bed  rock,  six  feet  above  the  stream, 
the  entire  structure  being  built  of  a  fine-grained  freestone,  quarried 
near  the  site ;  the  blocks  are  many  of  them  very  large,  only  two  or 
three  for  the  width  of  each  pier,  the  piers  having  triangular  cutwaters 
and  laid  in  courses  of  about  two  feet.  The  projecting  stones  or  cor- 
bels seen  on  various  parts  of  the  structure  were  used  to  support  the 
centering  on  which  the  arches  were  built. 

The  keystone  for  the  large  arch  is  5  feet  3  inches,  for  the  other 
large  spans  5  feet  and  for  the  small  ones  2  feet  7  inches.  The  arch 
stones  are  not  bonded  crosswise,  there  being  several  distinct  arches  in 
the  thickness. 

The  cut  stonework  is  laid  without  cement,  depending  on  nice  fit 
and  weight  for  solidity,  each  stone  having  been  lowered  into  place 
by  the  lewis ;  rubble  work  was  used  for  the  filling  in  of  the  piers, 
spandrells  and  haunches  of  the  first  and  second  stories,  and  for  the 
work  above  the  third  story  which  formed  the  water  conduit,  and 
which  was  laid  in  cement,  now  as  hard  as  the  rock  itself.  The  channel 
was  4  feet  in  width  by  4  feet  9  inches  in  height,  being  lined  with  2 
inches  of  cement  and  this  in  turn  covered  with  fine  dark  red  mastic, 
giving  a  surface  as  smooth  as  polished  marble;  the  channel  being 
covered  with  stone  slabs. 

The  arches  are  all  semi-circular  and  very  simple  as  was  the  Roman 
custom,  but  the  effect  is  magnificent  and  the  structure  worthy  of 
much  study. 


THE  BRIDGE  OF  THE  TRINITY,  FLORENCE. 

MORE  criticisms  have  been  written  concerningthe  bridge  of  the 
Trinity  at  Florence,  Italy,  than  perhaps  of  any  other  of  equal 
importance.   There  are  three  spans,  the  center  one  having 
a  clear  length  of  95  feet  10  inches  and  the  two  side  ones  87  feet  7 
inches,  with  a  rise  of  one-sixth  the  span.    The  piers,  as  can  be  seen 


11 


from  the  view  which  shows  one  side  span,  are  in  reality  abutments 
with  the  great  thickness  of  26  feet  3  inches  and  with  prominent 
acute-angled  starlings  both  up  and  dowrn  stream.  The  intrados  is 
made  up  of  two  parabolic  curves,  which  meet  at  the  center  with  a 
slight  angle,  which  is  concealed  with  a  large  escutcheon  that  ex- 
tends up  over  the  parapet  as  well.  The  piers  are  faced  with  cut 
stone,  the  moldings  being  very  elegant.  The  arch  ring  is  very 
heavily  molded  and  the  spandrels  paneled.  This  method  of  detail- 
ing is  not  so  inappropriate  for  spans  of  this  length  as  it  is  for  very 
large  spans  and  the  structure  presents  a  very  finished  and  elegant 
appearance. 

The  engineering  is  very  good  for  the  date  of  its  construction,  the 
year  1750,  the  design  being  that  of  Ammanati.  Had  the  two  piers 
been  made  of  only  ordinary  thickness  and  abutments  employed  pro- 
jecting out  from  the  river  walls,  the  proportions  would  have  been 
much  more  pleasing.  The  parapet  walls  are  of  perfectly  plain  design 
except  a  slight  molding  under  the  coping,  and  pedestals  at  the  ends 
which  are  surmounted  bv  statues. 


CANAL   REGIO,   BRIDGE,   VENICE. 

THE  fact  has  been  clearly  brought  out  in  the  description  of 
the  bridge  of  the  Rialto,  that  the  bridges  of  Venice  are 
more  a  part  of  the  architecture,  than  of  the  engineering 
of  the  city,  and  this  is  the  most  valid  excuse  for  the  employment  of 
architectural  details  in  their  embellishment. 

Artists  have  so  often  pictured  the  various  bridges  and  the  poets 
described  them  so  prominently  that  they  have  become  famed  the 
world  over.  Especially  is  this  true  of  the  Rialto  bridge  and  of  the 
Bridge  of  Sighs,  made  famous  by  Byron's  lines: 

"I  stood  in  Venice  on  the  Bridge  of  Sighs, 

"A  palace  and  a  prison  on  each  hand, 
"I  saw  from  out  the  waves  her  structures  rise, 
"As  from  the  stroke  of  the  enchanter's  wand." 

Some  of  the  less  noted  bridges  are  of  more  interest  to  the  engineer, 
where  the  bridge  effect  is  not  so  much  detracted  from  by  the  covered 
passages  or  arcades. 

The  span  over  the  Canal  Regio  has  steep  approaches  to  give  head- 
room over  the  canal,  but  steps  make  the  ascent  easy.  The  molded 
arch  ring  with  the  heads  in  relief  is  not  inappropriate  with  such  sur- 
roundings, and  the  balustrade  with  the  lofty  newels  heightens  the 
architectural  effect. 


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,    inch   and   o,                            >f  an   inch    between  oi:                    ii  of  an 
li  and  100  ft.                                                                                                  •  - .  .    -.00 
JOHNSON,  Prof.   J.                                                                                                                  <ud- 
a  Synopsis  of  the  I.                            is  and      i                                               Hn- 
•ering  Specification         >         ,.          »n,  conta                   litional    specifica- 
tions  for  electric  rail  |         

UN,   FRANK   C.,    "Tables  of  Radii 

Gyrations."       Flexible  leather,  s. ;   l~">  pp 

WRIGHT,  C.  H.  and  WING,  Prof.  C.  B.,  "Mam  ing."     F 

ble  canvas,  9%  X  12   ins.; 

ill-size  blue  prints  from  actual  working  cl:  

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ings."    Paper,  6x9   ins. ;    12  pp 

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10  pp 

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Structural  Steel."     Paper,  8%  X  13%  ins. ;    1.1   pp 

iB,  S.  M.,  "Tables  and  Diagrams  for  Making    •  for      Sow. -rage 

Work."  Paper,  oblong,  4%  x  7%  ins.;   20     pp.;     ,'  

THACHER,  .  EDWIN,      "General    Specifications    for  Hi  Pa- 
per, S  x  13%  ins. ;  8  pp 

Specifications  for  Railway  Bridges."      Paper, 
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NQINEERINO 
STUDIES 


PART  III 

ENGLISH   STONE   ARCHES 


BY  CHARLES  EVAN  FOWLER,  M.  AM.  Soc.  C.  E. 


Whoever  thinks  a  Faultless  piece  to  see, 

Thinks  what  ne'er  was,  nor  is,  nor  e'er  shall  be." 

'Content  if  hence  th'  unlearn'd  their  wants  may  view, 

The  learn'd  reflect  on  what  before  they  kn 

-Pop 


FIRST  EDITION. 


NEW  YORK. 

THE  ENGINEERING  NEWS  PUBLISH! 

1901. 


ENGINEERING 
STUDIES  " 


PART  HI 

ENGLISH   STONE   ARCHES 


BY  CHARLES  EVAN  FOWLER,  M.  AM.  Soc.  C.  E. 


"Whoever  thinks  a  Faultless  piece  to  see, 

Thinks  what  ne'er  was,  nor  is,  nor  e'er  shall  be." 
********* 

"Content  if  hence  th'  unlearn'd  their  wants  may  view, 
The  learn'd  reflect  on  what  before  they  knew." 

— Pope. 


FIRST  EDITION.     . 
NEW  YORK. 

THE   ENGINEERING   NEWS   PUBLISHING   CO. 

1901. 


Copyright,  1901,  by 
CHARLES   EVAN   FOWLER. 


GENERAL 


LONDON    BRIDGE. 

ONE  of  the  most  renowned  of  modern  stone  arch  bridges  is 
the  new  London  over  the  river  Thames.  It  is  also  one 
of  the  most  chaste  and  harmonious  designs  of  the  many 
stone  bridges  that  have  been  built  the  world  over,  and  was  Ren- 
nie's  masterpiece.  The  lack  of  waterway  under  the  old  bridge  had 
occasioned  great  public  controversy,  and  of  the  many  plans  pro- 
posed, the  one  from  which  the  bridge  was  constructed  seemed  to 
meet  best  the  needs  of  the  river,  of  navigation,  and  for  a  structure 
which  should  be  a  work  of  architecture. 

There  are  five  spans  of  elliptical  outline,  the  center  one  having 
a  span  of  152  feet,  a  rise  of  37.7  feet,  a  depth  of  arch  ring  at  the 
keystone  of  4.8  feet  and  at  the  spring  of  10.0  feet.  The  two  spans 
on  either  side  of  the  center  one  are  140  feet  each,  with  a  depth 
at  key  of  4.6  feet  and  at  spring  of  9.0  feet.  The  two  shore  spans 
have  a  span  of  130  feet  each,  a  depth  at  key  of  4.5  feet  and  at  spring 
of  8.5  feet. 

The  piers  were  founded  in  cofferdams,  one  of  which  was  car- 
ried 29  feet  6  inches  below  low  water.  The  stone  used  was  of 
granite,  and  the  masonry,  up  to  the  springing  of  the  arches,  was 
specified  to  be  ashler  in  horizontal  courses  of  from  15  to  24  inches 
thickness.  All  of  the  arch  stones  were  to  be  headers,  unless  the 
engineer  allowed  stretchers  to  be  used.  At  the  intrados  they  were 
to  be  18  inches  in  thickness  and  the  faces  dressed  smooth  and 
straight.  The  spandrels  between  the  arches  are  of  granite  and  the 
ring  stones  of  the  arch  are  tailed  into  the  spandrel  courses. 

The  cornice  and  parapets  are  also  of  granite,  finely  dressed  and 
jointed,  and  none  of  the  stones  belonging  to  the  cornice,  plinth, 
dado,  or  coping  were  allowed  less  than  4  feet  6  inches  long.  All 
these  stones  were  to  be  free  from  flaws  of  any  description. 

The  centers  for  turning  the  arches  were  composed  of  eight  ribs 
for  each  span,  each  rib  being  a  truss.  They  were  framed  at  the 
Isle  of  Dogs,  were  floated  to  the  bridge  site  and  raised  from  a 
large  barge  into  place  by  means  of  screws  and  the  tide.  On  these 
ribs  were  7-inch  plank  laid  close  to  carry  the  masonry. 

The  first  arch  laid  was  allowed  to  stand  the  entire  winter,  and 
when  the  wedges  were  struck,  the  arch  sank  an  inch  and  a  half, 
but  the  curve  was  not  broken. 

The  bridge  has  two  9-feet  sidewalks  and  a  roadway,  making  the 
entire  width,  face  to  face  of  masonry,  slightly  in  excess  of  56  feet. 
The  roadway  is  supported  on  longitudinal  arched  voids  and  has 
an  easy  grade. 

The  beautiful  elliptical  outline  of  the  arches  is  but  one  of  many 
details  by  which  an  appearance  of  elegance  is  obtained.  The 
starlings  of  almost  perfect  design  are  coped  and  capped  in  an 
appropriate  manner,  and  support  counterforts,  which  are  very 
effective  in  overcoming  any  tendency  toward  flatness  of  design. 
The  parapet  or  cornice  is  supported  by  corbels,  and  while  of  the 
simplest  design  is  in  entire  harmony  with  a  most  studied  and 
effective  piece  of  bridge  architecture. 

The  unsightliness  of  the  piping  which  is  laid  on  top  of  the  cor- 


nice  would  suggest  the  necessity  in  modern  structures  of  providing 
a  conduit  for  pipes,  wires  and  other  similar  appurtenances  of 
modern  civilization. 

The  bridge,  exclusive  of  land,  houses,  compensations,  and  law 
expenses,  cost  about  two  and  one-eighth  millions  of  dollars. 


THE    WATERLOO    BRIDGE. 

THIS  structure,  as  is  mentioned  in  the  description  of  the 
Krlso  bridge,  was  built  by  John  Rennie,  who  used  that 
one  as  his  model  for  what  is  probably  the  most  remark- 
able of  English  stone  arch  bridges.  The  roadway  being  nearly 
level  for  the  entire  length,  adds  much  to  the  appearance  of  a  work 
which  is  really  monumental.  There  are  nine  semi-elliptical  arch 
spans  of  120  feet  each,  with  a  rise  of  34.6  feet,  the  depth  of  the  arch 
ring  being  4  feet  6  inches  at  the  key,  and  10  feet  at  the  springing. 
The  keystone  is  not  accentuated  in  any  way,  and  all  the  arch  stones 
tail  into  the  spandrel  courses  in  groups,  all  joints  being  chamfered 
to  correspond  with  the  spandrel  masonry. 

The  piers,  which  were  founded  in  cofferdams,  have  semi-circu- 
lar ends,  being  30  feet  thick  at  the  base,  20  feet  at  the  spring,  with 
a  length  of  87  feet.  The  broad  abutments  have  staircases  down 
to  the  river,  are  40  feet  thick  at  the  base  and  30  feet  at  the  spring. 

All  the  exterior  masonry  is  of  dressed  granite,  and  the  filling 
is  of  Cragleigh  or  Derbyshire  stone.  Over  the  spandrels  are  rows 
of  columns  to  carry  the  roadway,  which  has  a  width  of  28  feet,  be- 
sides which  there  are  two  walks  of  7  feet  each. 

The  end  of  each  of  the  long  piers,  supports  two  severely  classic 
Doric  columns,  supporting  an  entablature,  and  it  is  almost  a  regret 
that  such  ornamentation  is  open  to  criticism  as  being  misplaced, 
as  has  been  done  in  describing  other  bridges  with  similar  details. 
When  compared,  however,  with  the  counterforts  on  the  London 
bridge  it  is  seen  that  nothing  has  been  gained  in  appearance  by  the 
use  of  columns. 

The  whole  structure  is  surmounted  by  a  well-designed  parapet 
and  balustrade  with  finely  detailed  turned  balusters.  Over  each 
keystone  is  "mis"-placed  a  lamp,  which  very  much  mars  the  other- 
wise grand  effect  of  the  bridge,  and  which  should  have  been  placed 
over  the  piers  instead. 

The  uneven  number  of  spans,  the  carefully  worked-out  design, 
the  character  of  the  engineering,  and  the  great  finish  of  the  whole 
work,  makes  this  one  of  the  most  notable  of  bridges  and  one  which 
will  bear  careful  studv  into  the  minutest  details. 


THE   MAIDENHEAD   ARCHES. 

THE  railway  bridge  at  Maidenhead,  England,  constructed  by 
Brunei,  in  1837,  is  an  example  of  the  grandeur  given  to 
engineering  works  by  simplicity  of  design.     The  two  large 
arches  are  elliptical,  with  a  span  of  128  feet,  a  rise  of  24.2  feet,  and 
a  depth  of  key  of  5.3  feet. 

The  spandrels  are  built  with  longitudinal  voids — the  bridge 

12 


of  brick  laid  in  cement.  The  curve  of  the  intrados  is  very  graceful 
and  the  whole  effect  is  one  of  boldness.  The  parapets  are  well 
proportioned  and  afford  the  relief  necessary,  while  the  abutments 
are  finely  accentuated  by  the  twin  pilasters. 

The  prevalence  of  such  work  gives  an  air  of  completeness  to  a 
landscape  and  one  has  reasonable  expectation  of  seeing  other  evi- 
dences of  civilization  in  its  neighborhood ;  and  this  is  not  disap- 
pointed, as  the  arch  bridge  seen  through  the  large  span  forms  part 
of  another  landscape  set  in  a  frame  of  masonry. 


KELSO    BRIDGE    OVER    THE    TWEED. 

THE  location  of  the  Kelso  bridge  is  near  the  junction  of  the 
Tweed  and  Tevoit  Rivers,  where  the  scenery  is  most  beau- 
tiful. It  was  designed  by  Rennie,  and  is  of  practically 
the  same  style  as  his  Waterloo  bridge,  which  was  built  at  a  later 
date.  There  are  five  equal  spans  of  72  feet  each  and  a  rise  of  20 
feet  9  inches,  while  the  width  is  26  feet.  The  arches  are  elliptical, 
with  the  arch  stones  tailed  into  the  spandrel  courses.  The  piers 
have  semi-circular  ends  and  support  two  Doric  columns  and  en- 
tablature, on  which  rests  the  cornice.  The  roadway  is  perfectly 
level  throughout,  and  is  guarded  by  solid  parapets,  with  retreats 
over  the  piers.  The  abutments  also  have  columns  supporting  the 
cornice,  and  quadrant  concave  wing  walls. 

The  severeness  of  the  design,  together  with  the  height  above 
the  stream,  gives  the  structure  an  imposing  appearance  and  makes 
it  appear  that  the  spans  are  quite  large.  The  ruins  of  Kelso  Abbey 
to  the  right  adds  materially  to  the  view.  This  bridge  was  com- 
pleted in  1799  and  the  Waterloo  bridge  begun  in  181 1.  The  Water- 
loo bridge  had  nine  elliptical  arches  of  120  feet  and  was  one  of 
the  first  bridges  constructed  over  the  Thames  with  the  roadway 
nearly  level. 

THE    CHATSWORTH    BRIDGE. 

WHILE  there  is  nothing  especially  remarkable  about  the 
Chatsworth  bridge,  it  is  a  typical  example  of  English 
Palace  accessories  in  bridge  engineering.  As  Chats- 
worth  House  is  considered  the  most  splendid  private  palace  in 
England,  it  is  to  be  expected  that  the  bridge  would  be  somewhat 
too  ornate.  It  is  almost  entirely  a  piece  of  architecture,  as  the 
engineering  problems  involved  in  its  construction  are  of  a  very 
simple  character. 

The  piers  are  well  proportioned,  and  are  capped  with  elegant 
molded  copings.  The  springing  of  the  arch  is  well  defined  and 
the  arch  ring  is  neatly  emphasized  by  a  molded  archivolt. 

The  statuary  over  the  pier  starlings  is  entirely  out  of  place  in 
bridge  design,  but  it  must  be  admitted  to  be  in  perfect  harmony  as 
part  of  a  group  of  architectural  works. 

The  beautiful  coping  and  balustrade  are  of  such  elegant  design  as 
to  be  worthy  of  much  study  and  imitation.  The  abutments  are 
elegantly  defined  and  it  is  to  be  regretted  that  a  work  otherwise  so 

13 


deserving  of  commendation,  should  have  its  beauty  impaired  by 
the  broken  profile  of  the  roadway,  which  could  easily  have  been 
avoided  by  a  gentle  curve  and  another  element  of  elegance  added. 


BROOMIELAW    BRIDGE,    GLASGOW. 

THIS  bridge  has  seven  segmental  arches,  the  center  span 
being  58  feet  6  inches  and  having  a  rise  of  10  feet  9  inches, 
the  two  adjacent  ones  57  feet  9  inches  span  and  10  feet  5 
inches  rise,  the  next  ones  55  feet  6  inches  span  and  9  feet  8  inches 
rise,  while  the  shore  spans  are  52  feet  3  inches.  The  piers  range 
in  thickness  from  8  to  9  feet  and  have  octagonal  ends,  supporting 
octagonal  counterforts,  which  carry  the  pedestals  and  lamps.  The 
bridge  has  two  sidewalks  and  a  roadway  with  two  car  tracks,  mak- 
ing up  a  total  width  of  58  feet  in  the  clear  between  parapets.  The 
arch  ring  is  composed  of  uniform  ring  stones  with  chisel  draft  on 
all  edges,  while  the  spandrels  are  paneled.  The  balustrade  has 
turned  balusters  and  a  pilaster  over  each  keystone.  The  piers  and 
abutments  are  of  freestone,  while  the  face  work  of  the  arches  and 
spandrels  is  of  granite. 

The  bridge  was  designed  by  Telford,  who  is  credited  with  having 
built  upwards  of  eleven  hundred  stone  bridges,  having  over  twelve 
hundred  arches. 

The  foundations  were  built  in  cofferdams  having  a  five  or  six 
feet  puddle  chamber.  Piles  were  driven  for  the  foundations,,  cut 
off  to  a  level,  and  capped  with  grillage  platforms  on  which  to  lay  the 
masonry.  The  paving  for  the  roadway  is  laid  upon  concrete,  the 
sidewalks  are  of  flat  stone,  the  12-inch  curb  of  granite  has  the 
angle  rounded  off,  while  the  gutter,  also  of  granite,  is  14  inches 
wide  and  has  a  triangular  channel  cut  in  it,  8  inches  wide  and  4 
inches  deep. 

THE    NEW    BRIDGE    OF    AYR. 

THE  "Twa  Brigs  o'  Ayr"  have  been  made  famous  by  the 
poet  Burns,  one  of  the  bridges  being  the  old  one  in  the 
background  which  is  now  used  only  for  foot  passage, 
while  the  new  one  in  the  foreground  occupies  the  site  of  the  other, 
the  present  bridge  being  the  third  to  occupy  the  same  place.  The 
bridge  consists  of  five  spans  of  small  rise,  the  side  spans  being 
somewhat  shorter  than  the  other  three.  The  arch  stones  are  tailed 
into  the  spandrel  courses  in  a  very  pleasing  manner  and  the  key- 
stones accentuated  by  a  pyramidal  face.  The  piers  have  rounded 
ends,  with  appropriate  coping  and  caps,  and  are  surmounted  by 
counterforts  with  molded  tops.  The  dentiled  cornice,  while  very 
plain,  is  of  neat  design,  being  broken  over  the  piers  by  the  orna- 
mental brackets  which  support  the  pedestals  of  the  balustrade. 

The  parapets  or  balustrades  are  of  very  beautiful  design,  that 
over  each  arch  being  divided  into  several  sections  by  paneled  pilas- 
ters, each  section  having  four  circular  openings  in  the  dado  with 
other  simple  but  effective  decoration,  except  that  the  long  spans 
have  an  extra  panel  at  the  center  with  only  one  opening.  At  the 

14 


ends  and  over  each  pier  there  are  pedestals  carrying  ornamental 
(amp  posts. 

The  contrast  with  the  old  bridge  is  very  great  and  is  a  strik- 
ing illustration  of  the  progress  made  in  bridge  design.  Scarcely 
anv  fault  is  to  be  found  with  the  appearance  of  the  new  bridge 
unless  it  is  the  lack  of  more  prominent  abutments  at  both  ends, 
there  being  an  appearance  of  the  bridge  having  been  crowded  in 
between  the  river  walls. 


THE    GROSVENOR    BRIDGE. 

THE  fourth  largest  stone  span  in  existence  is  the  one  built 
at  Chester,  England,  over  the  river  Dee,  from  the  plans 
of  Mr.  Harrison,  an  architect  of  that  city.     It  is  known 
as  the  Grosvenor  or  Chester-Dee  bridge.    The  span  is  exactly  200 
feet,  the  rise  42  feet,  the  depth  at  key  4.5  feet,  at  spring  7.0  feet, 
while  the  roadway  is  33  feet  in  width. 

The  following  description  of  the  bridge  is  taken  from  Cresy : 
"The  bridge  is  situated  between  the  castle  and  the  village  of 
Overlegh,  immediately  at  the  head  of  the  harbor,  where  the  tide 
rises  12  feet  at  ordinary  springs.  The  abutments  are  founded  on 
the  solid  rock,  except  for  a  small  portion,  where  it  was  necessary 
to  pile.  The  arch  is  the  segment  of  a  circle  whose  radius  is  140 
feet,  and  the  rise,  or  versed  sine,  42  feet.  The  voussoirs  at  the 
crown  are  4.5  feet  deep,  and  increase  toward  the  springing,  where 
they  are  7  feet.  The  center,  executed  by  Mr.  Trubshaw,  the  con- 
tractor, consisted  of  six  ribs  in  width ;  the  span  of  the  arch  was 
divided  into  four  spaces  by  three  piers,  at  regular  distances,  built 
up  in  the  river,  from  which  the  timbers  spread  like  a  fan  towards 
the  soffit,  so  that  each  timber  received  its  weight  in  the  direction 
of  its  length ;  the  lower  ends  of  these  radiating  supports  rested  on 
cast-iron  shoes,  placed  on  the  tops  of  stone  piers,  and  the  upper 
ends  were  bound  together  by  two  thicknesses  of  4-inch  plank,  cut 
and  arranged  to  follow  the  form  of  the  arch ;  on  these  were  laid 
the  lagging  or  covering,  4^  inches  thick,  which  was  supported  over 
each  rib  by  a  pair  of  folding  wedges  16  inches  long  and  I  foot 
broad,  tapering  about  i/^  inches;  each  course  of  voussoirs  has 
six  pair  of  striking  wedges.  The  horizontal  timbers  of  the  center 
were  13  inches  deep,  and  the  six  ribs  were  tied  together  trans- 
versely near  the  top  by  bolts  of  inch  iron ;  the  timber  used  was  fir, 
and  the  quantity  required  about  10,000  cubic  feet.  When  the 
center  was  removed  the  crown  sunk  only  2^/2  inches.  The  cost  of 
the  bridge  was  £42,400,  and  the  approaches  £7,500,  making  a  total 

of  £49,900-" 

In  several  previous  examples,  quotations  from  Fergusson's  crit- 
icism on  this  bridge  have  been  given,  so  that  it  would  seem  ap- 
propriate to  quote  in  full  what  he  has  to  say  concerning  it.  While 
quite  severe  in  tone,  it  must  be  said  that  personal  inspection  of 
the  bridge  invites  respect  for  the  bridge  and  for  the  designer. 

Fergusson  says : 

"In  all  these  cases  the  primary  object  of  the  engineer  is  use,  not 
beauty;  but  he  cannot  help  occasionally  becoming  an  architect, 
and  sometimes  with  singular  success,  though  too  frequently,  when 

15 


he  ornaments,  it  is,  as  architects  generally  do.  bv  borrowing  feat- 
ures from  the  Classical  or  Mediaeval  styles,  or  by  some  mistaken 
application  of  them,  betraying  how  little  he  has  really  studied  the 
problem  before  him. 

"In  illustration  of  these  definitions,  let  us  take  the  Dee  bridge  at 
Chester.  As  an  engineering  work,  nothing  can  be  nobler.  It  is 
the  largest  single  span  for  a  stone  bridge  in  England,  probably  in 
the  world ;  built  of  the  best  materials,  and  in  a  situation  where  noth- 
ing interferes  with  its  beauty  or  proportions.  Its  engineer,  how- 
ever, aspired  to  be  architect ;  and  the  consequence  is,  that  instead 
of  giving  value  to  an  arch  of  200  feet  span,  no  one  can,  by  mere 
inspection,  believe  that  it  is  more  than  half  that  width.  In  the 
first  place,  he  introduced  a  common  architrave  moulding  round  the 
arch,  such  as  is  usually  employed  in  domestic  architecture,  and 
which  it  requires  immense  thought  to  exaggerate  beyond  the  di- 
mensions of  a  porte-cochere.  He  then  placed  in  the  spandrels  a 
panel  30  feet  by  50,  which,  in  like  manner,  we  are  accustomed  to, 
of  one-third  or  one-thirtieth  these  dimensions.  He  then,  on  his 
abutments,  introduced  two  niches  for  statues,  which  it  is  imme- 
diately assumed  would  be  of  life  size ;  and  beyond  this,  two  land- 
arches  without  mouldings  or  accentuations  of  any  sort,  conse- 
quently looking  so  weak  as  to  satisfy  the  mind  there  was  no  diffi- 
culty in  the  construction. 

''Had  Mr.  Harrison  been  really  an  architect,  he  would  have  rus- 
ticated these  land-arches  with  Cyclopean  massiveness,  not  only  to 
continue  the  idea  of  the  embankment,  but  also  to  give  strength 
where  it  was  apparently  most  needed ;  and  would  have  avoided  any- 
thing in  the  abutments  that  savored  of  life-size  sculpture  or  of 
temple  building.  A  Mediaeval  architect  would  have  pierced  the 
spandrels  with  openings,  thereby  giving  both  lightness  and  dimen- 
sions to  this  part ;  or,  if  that  was  not  mechanically  admissible,  he 
would  have  divided  it  into  three  or  four  panels,  in  accordance  with 
the  construction.  The  essential  parts  in  the  construction  of  a  bridge, 
however,  are  the  voussoirs  of  the  arch ;  and  to  this  the  architect's 
whole  attention  should  first  be  turned.  If  there  had  been  fifty  well- 
defined  arch  stones,  the  bridge  would  have  looked  infinitely  larger 
than  it  now  appears.  With  one  hundred  it  would  have  looked 
larger  still;  but,  if  too  numerous,  there  is  a  danger  of  the  struc- 
ture losing  that  megalithic  character  which  is  almost  as  essential 
as  actual  dimensions  for  greatness  of  effect.  The  true  architect  is 
the  man  who  can  weigh  these  various  conditions  one  against  the 
other,  and  strike  a  judicious  balance  between  the  different  ele- 
ments at  his  command.  At  Chester  the  builder  has  failed  in  this 
at  every  point,  and  by  the  same  process  which  ruined  St.  Peter's. 
By  exaggerating  his  details,  the  bridge  has  been  dwarfed  in  ex- 
actly the  same  manner  as  the  basilica. 

"If  this  is  all  that  can  be  done  with  bridges,  it  is  far  better  that 
they  should  be  left,  like  most  of  those  recently  built,  to  tell  their 
own  tale  without  any  ornament  whatever.  A  long  series  of  tall 
arches  is  so  beautiful  an  object  in  itself  that  it  is  difficult  to  injure 
it;  but  occasionally  a  slight  moulding  at  the  impost,  a  bold  ac- 
centuation of  the  arch,  and  bold  marking  of  the  roadway  render 
those  beautiful  which  otherwise  may  only  be-  useful  in  appearance/1 

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ENGINEERING 
STUDIES 


PART  IV 


STONE   ARCHES 


:HARLES  EVAN  FOWLER,  M.  AM. 


Whoever  thinks  a  Faultless  piece  to  see, 
Thinks  what  ne'er  was,  nor  is,  nor  e'er  shall  be. " 
********* 
Content  if  hence  th'  unlearn'd  their  wants  may  view, 
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FIRST  EDITION 


NEW  YORK. 

INEERING  NEWS  PUBLISH1NC 
1903. 


ENGINEERING 
STUDIES'" 


PART  IV 


FRENCH   STONE   ARCHES 


BY  CHARLES  EVAN  FOWLER,  M.  AM.  Soc.  C.  E. 


Whoever  thinks  a  Faultless  piece  to  see, 
Thinks  what  ne'er  was,  nor  is,  nor  e'er  shall  be." 
********* 
'Content  if  hence  th'  unlearn'd  their  wants  may  view, 
The  learn'd  reflect  on  what  before  they  knew." 

—Pope. 


FIRST  EDITION. 
NEW   YORK. 

THE  ENGINEERING  NEWS  PUBLISHING  CO. 

1903. 


Copyright,   1903,  by 
CHARLES    EVAN    FOWLER. 


10 


BRIDGE   OF    ORLEANS. 

AMONG  the  oldest  of  modern  stone  bridges  in  France  is  the 
bridge  at  Orleans,  constructed  from  designs  of  the  en- 
gineer Hupeau,  between  1750  and  1760.  There  are  nine 
elliptical  spans,  the  shortest  being  98  feet  and  the  longest  106.5 
feet,  and  they  are  more  pleasing  than  many  others  of  similar  out- 
line by  reason  of  the  curve  of  the  intrados  finishing  tangent  to  the 
face  of  piers.  The  arch  stones  are  dentiled  into  the  spandrel  ma- 
sonry, the  entire  masonry  work  of  the  bridge  being  dressed  work. 
The  rise  of  the  arches  is  from  16  feet  in  the  shortef~spans  to  28.8 
feet  in  the  longer  ones,  the  thickness  of  the  arch  rings  being  5.8 
and  6.9  feet  respectively. 

The  piers  range  from  18.1  to  19.2  feet  in  thickness,  and  the  semi- 
circular ends  extend  upwards  above  the  curve  of  the  extrados, 
with  coping  and  stepped  conical  capping,  which  gives  the  bridge 
great  individuality.  The  neatly  laid  ripraping  around  the  piers 
also  adds  to  their  finished  appearance. 

The  piers  were  founded  on  piles  and  a  grillage,  the  piles  being 
driven  through  a  bed  of  sand  from  4  to  13  feet  in  thickness  into 
the  underlying  hard  layers.  A  great  deal  of  water  was  encoun- 
tered, and  the  pumping  was  no  small  part  of  the  cost  of  the  foun- 
dations. One  of  the  piers  settled  i  foot  and  7  inches,  and  some 
considerable  settlement  took  place  after  the  bridge  was  completed, 
which  was  stopped  by  the  driving  of  additional  piles  outside,  to- 
gether with  ripraping. 

The  width  of  the  bridge  from  face  to  face  of  masonry  at  the 
crown  is  49  feet.  A  molded  cornice  or  coping  supports  a  very  plain 
parapet  wall,  which  agrees  well  however  with  the  massive  charac- 
ter of  the  entire  structure. 

The  cost  of  the  bridge  was  very  close  to  half  a  million  dollars, 
including  the  later  additional  work. 


THE    PONT    NEUF,  PARIS. 

THE  most  famous  bridge  to  be  seen  in  Paris  is  the  Pont  Neuf. 
It  was  begun  in  1578  under  Henry  III.  from  the  plans  of 
Andronet  dn  Cerceau.  The  wars  interrupted  its  progress, 
and  it  was  recommenced  in  1602  under  Henry  IV.,  being  com- 
pleted in  1607. 

The  river  Seine  is  divided  at  this  point  by  an  island,  and  the 
bridge  is  in  two  sections,  one  on  each  side  of  this  island.  One  sec- 
tion has  seven  arches  ranging  from  46  feet  to  62  feet  4  inches  in 
span,  while  the  other  section  has  only  five  arches  ranging  from  31 
feet  3  inches  to  48  feet,  all  the  spans  being  semi-circular. 

The  entire  width  of  the  bridge  is  72  feet,  part  of  it  overhanging 
the  arches,  being  supported  by  brackets.  The  piers  have  triangu- 
lar cut-waters,  which  carry  triangular  counter-forts  up  to  the 
cornice. 

The  space  between  the  two  portions  of  the  bridge  is  ornamented 
by  the  equestrian  statue  of  Henry  IV.  Here  is  where  Napoleon 

II 


made  his  famous  stand  during  the  French  Revolution,  before  his 
name  had  been  made  famous. 

The  splendid  condition  of  the  masonry  after  such  long  usage, 
under  very  heavy  traffic,  attests  the  careful  study  given  to  the  de- 
sign and  the  care  with  which  the  work  was  done.  The  bridge  is 
not  an  example  to  be  copied  with  profit,  but  is  an  example  of  the 
character  which  is  given  to  an  engineering  work  by  a  massive 
design. 

BORDEAUX    BRIDGE. 

THE  seventeen  arch  spans  over  the  Garonne  River  at  Bor- 
deaux is  one  of  the  most  remarkable  stone  bridges  in 
existence.  It  was  constructed  between  the  years  1813 
and  1822  by  the  French  engineer  Deschamps,  and  while  the  great- 
est span  is  only  86.9  feet,  the  great  number  of  arches  renders  it 
very  imposing  by  reason  of  length  alone. 

Not  by  any  means  ornate,  its  chaste  design  renders  it  still  more 
striking.  The  ends  are  flanked  by  guard  houses  of  very  simple 
design,  but,  as  may  be  seen  from  the  view,  they  are  in  entire  har- 
mony with  the  bridge  itself.  The  parapet  wall,  while  perfectly 
plain  and  free  from  ornament,  does  not  mar  the  design,  resting  as 
it  does  on  a  neat  coping  course,  supported  by  corbels  or  brackets. 

The  arches  are  elliptical,  with  a  rise  of  28.9  feet,  the  thickness  at 
the  crown  being  3.9  feet.  The  piers  are  semi-circular  on  the  ends, 
with  caps  which  form  a  neat  and  fitting  finish,  the  thickness  be- 
ing 13.8  feet. 

The  bed  of  the  river  is  only  mud  and  sand,  the  borings  showing 
a  depth  of  from  39  to  52  feet  to  hard  material,  so  that  two  hundred 
and  fifty  piles  were  driven  under  each  pier,  cut  off  approximately 
twelve  feet  below  water,  and  loose  rock  filled  in  around  their  tops 
to  steady  them  before  beginning  the  masonry. 

The  material  used  in  the  construction  was  brick  and  stone. 


ROQUEFAVOUR   AQUEDUCT. 

WITH  the  old  Roman  Aqueduct  at  Nimes  as  an  inspira- 
tion, it  is  not  surprising  that  de  Montricher  should 
have  conceived  the  Aqueduct  of  Roquefavour  near 
Marseilles  in  France.  With  fifteen  arches  of  52.5  feet,  and  reach- 
ing upwards  from  the  bottom  of  the  valley  to  the  great  height  of 
271  feet,  with  studied  elegance  of  design,  detail  and  workmanship, 
it  is  not  surprising  either  that  the  Pont  du  Card  should  be  so  far 
eclipsed.  Being  the  highest  stone  bridge  in  the  world,  its  slender 
piers  are  braced  by  arches  low  down  which  give  the  structure  a 
three-storied  effect.  Projecting  belt  courses  relieve  the  piers  at 
the  springing  of  all  the  arches,  which  are  circular,  there  being  re- 
lieving counterforts  on  the  piers  between  the  large  arches  of  the 
top  story.  The  canal  or  aqueduct  is  carried  by  52  small  arches  in 
the  top  story,  the  span  of  each  arch  being  16.4  feet. 

12 


Not  without  some  study  is  it  discovered  why  this  story  is  so  in- 
finitely more  pleasing  in  effect  than  the  corresponding  portion  of 
its  famous  prototype ;  the  reason  is  very  simple,  each  large  arch 
is  surmounted  by  three  small  arches — an  uneven  number — and 
symmetrically  disposed  throughout  the  structure.  Surmounted 
by  a  cornice,  composed  of  a  well  proportioned  capping  supported 
by  consoles,  the  effect  of  the  entire  structure  is  most  pleasing,  be- 
ing simple,  harmonious  and  commanding  admiration. 


THE   PONT   AU    CHANGED, 

FRANCE,  holding  a  position  pre-eminently  among  nations 
as  a  builder  of  stone  bridges,  it  is  to  be  expected  that  in 
Paris  would  be  found  remarkable  examples  of  this  de- 
partment of  bridge  engineering.  It  is  doubtless  evident  from  the 
illustrations  that  the  bridges  of  this  most  wonderful  of  the  world's 
cities  were  constructed  to  give  uninterrupted  flow  to  street  traffic 
across  the  Seine.  This  is  well  illustrated  in  the  view  of  the  road- 
way of  the  Pont  Neuf,  but  perhaps  better  shown  in  the  view  of  the 
Pont  au  Change,  where  the  bridge  is  the  full  width  of  the  street, 
and  except  for  the  balustrades  on  either  side,  in  place  of  enclosing 
buildings,  it  would  not  seem  different  from  the  avenue  approach- 
ing it  from  both  directions. 

Not  satisfied  with  having  designed  a  structure  of  maximum 
utility,  the  engineer  gave  to  the  arches  a  beauty  comparable  with 
other  Parisian  bridges  and  architecture.  Nothing  certainly  can 
exceed  in  beauty  an  elliptical  outline  for  an  arch,  and  the  details 
are  in  harmony  with  the  general  design.  It  is  to  be  regretted, 
however,  that  the  break  in  grade  was  not  overcome  by  a  vertical 
curve.  The  same  fault  is  to  be  found  with  this  as  with  many  simi- 
larly designed  bridges,  in  that  the  springing  of  the  arches  is  con- 
cealed, and  in  the  lack  of  abutments  at  the  shore  ends  instead  of 
the  abrupt  ending  in  the  shore  wall,  which  was  rendered  necessary 
by  the  provision  of  a  proper  waterway.  The  decorative  imperial 
wreath  and  N  is  too  large  and  could  have  been  made  one-fourth 
smaller  to  the  enhancement  of  the  beauty  of  the  entire  design. 
With  these  criticisms,  however,  it  must  be  said  that  no  serious 
fault  can  be  found  with  these  beautiful  engineering  creations, 
which  are  subject,  like  all  else  in  this  world,  to  mistakes  of  judg- 
ment. 


THE   AUTEIL   VIADUCT. 

TO  no  countrty  can  the  engineer  turn  for  the  study  of  bridge 
architecture  with  the  same  degree  of  satisfaction  as  to 
France.     The  easily  discerned  cause  for  this    was    the 
early  organization  of  the  Ecole  de  Pont  et  Chaussees,  which  insti- 
tuted a  system  in  the  engineering  endeavor  of  France. 

The  greatest  perfection  has  been  attained  in  the  bridges  across 
the  Seine  at    Paris,    where    naturally   the    expenditure    has    been 

13 


most  lavish  in  the  direction  of  architecture.  The  Auteil  viaduct 
crosses  the  Seine  with  five  large  arch  spans,  five  of  which  can  be 
seen  in  the  view.  The  piers  are  of  beautiful  design  and  appropri- 
ately coped,  while  the  arch  ring  is  accentuated ;  the  only  possible 
fault  being  the  concealment  of  the  springing.  The  ornamenta- 
tion of  the  spandrel  filling,  above  the  pier,  with  the  imperial  "N," 
adds  much  to  the  design ;  the  coping  course,  supported  by  corbels, 
is  surmounted  by  an  elegant  balustrade.  This  story  carries  a  road- 
way, while  the  viaduct  proper  is  carried  above  on  thirty-one  small 
arches,  the  supporting  piers  being  pierced  with  two  arches  cross- 
wise. A  balustrade,  in  entire  harmony  with  the  one  on  the  first 
story,  surmounts  the  whole  structure,  while  the  connection  with 
the  approaches  is  effected  by  a  very  flat  segmental  arch  on  each 
side. 

The  unquestioned  elegance  of  the  viaduct  was  not  obtained  by 
the  employment  of  any  details  except  those  absolutely  necessary 
for  the  structural  execution  of  the  work,  nor  could  anything  fur- 
ther be  added  without  detracting  from  its  finished  appearance. 


PONT    DE    AUSTERLITZ 

NAPOLEON  at  St.  Helena,  in  recounting  the  deeds  and 
works  for  which  he  would  be  remembered,  did  not  fail 
to  mention  the  bridges  he  had  caused  to  be  constructed, 
for  of  the  engineering  works  constructed  during  his  reign  he  was 
justly  proud.  Between  the  years  1804  and  1813  he  expended  for 
bridges  alone  the  sum  of  39,305,000  francs,  of  which  sum  3,000,000 
francs  were  for  the  bridge  of  Austerlitz.  This  bridge  was  built 
to  commemorate  the  victory  of  Austerlitz — the  greatest  of  his  vic- 
tories— as  others  of  his  bridges  were  constructed  as  monuments 
to  other  battles  where  he  was  victorious.  That  he  did  not  mistake 
in  choosing  his  monuments  is  evidenced  by  the  interest  yet  taken 
in  the  works  of  his  engineers  and  from  the  fact  that  these  bridges 
are  as  worthy  of  study  to-day  as  they  were  scores  of  years  ago. 

The  Pont  de  Austerlitz  is  in  the  first  place  a  work  of  architecture 
because  of  the  division  of  the  crossing  into  five  spans,  an  odd 
number  being  the  most  elementary  feature  necessary  to  perfection 
of  design.  The  arch  ring  stands  out  bold  and  in  full  relief,  with 
the  springing  of  the  arches  in  full  view — not  concealed  as  is  the 
case  with  many  stone  bridges  which  are  otherwise  remarkably 
near  perfection.  The  flatness  of  the  arches  is  in  pleasing  contrast 
to  those  of  more  rise  and  consequently  of  greater  boldness.  The 
piers  on  this  account  become  mere  supports  to  the  superstructure 
and  are  well  designed  to  this  end.  Above  them  decorating  the 
spandrels  are  the  palm  leaves,  wreath,  and  imperial  "X"  sur- 
mounted by  the  crown,  emblematic  of  victory  and  empire — fixing 
beyond  question  the  purpose  of  the  construction.  The  balustrade 
is  of  chaste  design,  unbroken  in  detail  except  over  the  piers, 
where  a  short  panel  marks  the  spacing  of  the  spans  and  serves  to 
break  the  monoton. 


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ENGINEERING 
STUDIES 

PART  V 

GERMAN  AND  AUSTRIAN 
STONE  ARCHES 

BY  CHARLEf    EVAN  FOWLER,  M.  AM.  Soc.  < 


Whoever  thinks  a  Faultless  piece  to  see, 
Thinks  what  ne'er  was,  nor  is,  nor  e'er  shall  be. " 
*        *        *        *        *        *        *        *        * 
Content  if  hence  th'  unlearn'd  their  wants  may  view, 
The  learn'd  reflect  on  what  before  they  knew," 


FIRST  EDITION. 
NEW  YORK. 

ENGINEERING  NEWS  PUBLISHING  CO 
1903 


ENGINEERING 
STUDIES 

PART  V 

GERMAN  AND  AUSTRIAN 
STONE  ARCHES 

BY  CHARLES  EVAN  FOWLER,  M.  AM.  Soc.  C.  E. 


Whoever  thinks  a  Faultless  piece  to  see. 
Thinks  what  ne'er  was,  nor  is,  nor  e'er  shall  be." 
********* 
Content  if  hence  th'  unlearn'd  their  wants  may  view, 
The  learn'd  reflect  on  what  before  they  knew." 

— Pope. 


FIRST  EDITION. 
NEW   YORK. 

THE  ENGINEERING  NEWS  PUBLISHING  CO. 

1903. 


^NERAL1 


Copyright,   1903,  by 
CHARLES    EVAN    FOWLER. 


IO 


DRESDEN    BRIDGE. 

THE  old  and  new  towns  of  Dresden  are  separated  by  the 
river  Elbe,  and  communication  is  had  over  the  stone  bridge 
constructed  from  designs  of  Engineer  Fotins,  between 
1179  and  1260. 

There  are  eighteen  arches  of  72  feet  6  inch  span,  with  a  rise  of 
36.3  feet.  The  arch  ring  is  6.4  feet  thick  at  the  crown,  and  the 
width  of  the  bridge  is  37.3  feet. 

The  piers  cover  a  large  area  on  the  base,  and  extending  out  so 
much  beyond  the  roadway,  are  formed  into  retreats,  which  gives 
the  bridge  a  very  novel  appearance.  The  bridge  is  widened  by  the 
brackets  under  the  sidewalks,  which  are  the  only  ornamental  feat- 
ures of  the  structure,  as  everything  else  is  of  the  greatest  plainness, 
and  the  parapet  railing  is  an  ordinary  iron  one. 

There  is  nothing  in  Dresden  to  at  all  compare  with  the  architec- 
ture at  Munich,  and  consequently  the  bridge  is  not  so  out  of  keep- 
ing with  its  surroundings  as  would  be  true  if  located  in  a  city  with 
more  magnificent  architecture. 


THE   OBERBAUMBRUCKE. 

THE  electric  railways  of  Berlin  are  of  such  excellent  construc- 
tion as  to  have  been  the  subject  of  many  descriptive  arti- 
cles.      By  excellent  is  meant  not  only  the  best  and  most 
solid  construction,  but  elegance  and  beauty  of  design  of  the  struc- 
tures.    A  recent  writer  says :    "The  one  respect  in  which  the  Ger- 
man constructors  leave  others  far  behind  and  offer  an  object  lesson 
worth  careful  study,  is  in  the    artistic    beauty,    the    architectural 
charm  and  sense  of  fitness  which  they  have  imparted  to  the  stations, 
the  bridges,  and  even  the  ordinary  overhead  viaduct  sections  of  the 
new  road. 

Elevated  railways  in  America,  for  example,  are  admittedly  effi- 
cient and  well  managed;  they  run  spacious,  well-ventilated,  com- 
fortable cars  at  high  speed,  for  fares  which  are  very  low  in  com- 
parison with  carriages  and  other  means  of  transportation.  But 
they  are  for  the  most  part  plain  and  commonplace  in  appearance, 
and  the  stations,  even  in  central  and  populous  precincts,  are  often 
buildings  which  are  considered  blemishes  to  the  neighborhood. 
Here  the  requirements  of  public  taste  are  never  permitted  to  be 
neglected  or  forgotten.  Where  a  new  Berlin  line  passes  through  a 
public  square,  it  is  on  solid  and  artistically  designed  masonry.  The 
above  ground  stations  are  of  stone,  steel,  and  glass,  no  two  alike, 
but  each  specially  designed  to  fit  not  only  the  requirements  of 
traffic  at  that  point,  but  the  adjacent  buildings  as  well — the  archi- 
tectural frame-work  in  which  it  is  set.  Where,  for  instance,  shall 
we  look  outside  of  continental  Europe  for  interurban  railway  sta- 
tions like  those  at  the  Schlesisches  Thor,  and  the  Nollendorfer 
Platz,  or  a  bridge  like  the  Oberbaumbrucke,  on  which  this  new  Ber- 
lin line  crosses  the  Spree?" 

ii 


This  has  been  illustrated  in  the  Studies  to  emphasize  the  possi- 
bilities in  the  artistic  design  of  the  structures  of  our  every-day 
utilities.  With  such  an  ornate  bridge,  rather  too  ornate  than 
otherwise,  the  necessity  for  destroying  the  effect  by  such  guard 
piles  and  fenders  is  certainly  to  be  deplored. 


MUNICH    BRIDGE 

MUNICH  is  one  of  the  great  art  centers  of  Europe,  and  has 
many  renowned  works  of  architecture,  and  which  individ- 
ually are  deserving  of  great  admiration,  although  in  gen- 
eral the  subject  of  much  criticism.  Fergusson  says,  regarding  the 
works  executed  during  the  reign  of  King  Louis  of  Bavaria : 

"\Vhen  a  young  man,  residing  at  Rome,  as  Crown  Prince  of 
Bavaria,  Louis  seems  to  have  been  struck  with  admiration  for  the 
great  works  he  saw  there,  and  from  their  contemplation  to  have 
imbibed  a  love  of  Art,  which  led  him  to  resolve  that  when  he  came 
to  the  throne  he  would  devote  his  energies  to  the  restoration  of 
German  Art.  and  make  his  capital  the  central  point  of  the  great 
movement  he  was  contemplating.  Earnestly  and  perseveringly 
he  worked  towards  this  end  during  die  whole  of  his  reign;  and  if 
the  result  has  not  been  so  satisfactory  as  might  be  wished,  it  has 
not  been  owing  either  to  want  of  means  or  of  encouragement  on 
the  part  of  the  king,  but  to  the  system  on  which  he  proceeded, 
either  from  inclination,  or  from  the  character  of  the  agents  he  was 
forced  to  employ  in  carrying  out  his  designs. 

''The  ruling  idea  of  the  Munich  School  of  Architecture  seems  to 
have  been  to  reproduce  as  nearly  as  possible  in  facsimile  every 
building  that  was  great  or  admirable  in  any  clime,  or  at  any  pre- 
vious period  of  history,  wholly  irrespective  either  of  its  use  or  of 
the  locality  it  was  destined  to  occupy  in  the  new  capital.  Whatever 
the  king  had  admired  abroad  his  architects  were  ordered  to  repro- 
duce at  home.  The  consequence  is  that  Munich  is  little  more  than 
an  ill-arranged  museum  of  dried  specimens  of  foreign  styles,  fre- 
quently on  a  smaller  scale,  and  generally  in  plaster,  but  reproduc- 
ing with  more  or  less  fidelity  buildings  of  all  ages  and  styles,  though 
in  nine  cases  out  of  ten  designed  for  other  purposes,  and  carried 
out  in  different  materials. 

"Had  the  king,  on  the  other  hand,  insisted  that  his  architects 
should  copy  nothing,  but  must  produce  buildings  original  in  de- 
sign, and  adapted  to  the  climate  of  Germany  and  the  usages  of  the 
nineteenth  century,  he  had  it  in  his  power  to  be  the  founder  of  a 
School  of  Art  which  would  have  rendered  his  name  illustrious  in 
all  future  ages.  Probably  such  a  conception  was  as  much  beyond 
the  calibre  of  the  royal  patron's  mind  as  it  might  have  exceeded  the 
talent  of  his  artists  to  execute  it.  Unfortunately,  the  reproduction 
of  the  Parthenon  or  the  Pitti  Palace  enabled  flatterers  to  suggest 
that  he  had  equalled  Pericles  or  the  Medici ;  and  it  was  not  thought 
necessary  to  hint  that  the  printer,  who  multiplies  the  work  of  a 
great  poet,  need  not  necessarily  be  as  great  as  the  author  of  the 

12 


first  conception.  To  the  architects  it  was  Elysium ;  they  had  only 
to  measure  and  repeat;  authority  sanctioned  all  blunders  and  re- 
lieved the  artist  from  all  responsibility. 

"The  experiment  was  so  novel,  at  least  in  Germany,  that  it  was 
at  first  hailed  with  enthusiasm ;  but,  after  this  had  subsided,  the 
taste  of  the  nation  recoiled  from  the  total  want  of  thought  dis- 
played in  the  buildings  at  Munich,  and  their  common  sense  re- 
volted at  their  want  of  adaptation  to  the  circumstances  in  which 
they  are  placed.  The  result  may  eventually  prove  fortunate  for 
the  development  of  the  art  of  Architecture.  The  king  placed  be- 
fore his  countrymen  specimens  of  all  schools  and  all  styles;  and 
the  contemplation  of  these  may  arouse  the  German  mind~to  emu- 
late their  beauties  instead  of  servilely  copying  their  details.  But 
meanwhile  the  mind  of  the  student  is  puzzled  by  the  variety  of  ex- 
amples submitted  for  his  admiration.  Is  it  the  Walhalla  or  the 
Aue-Kirche  he  is  to  admire?  The  Konigsbau  or  the  Wittel- 
bacher  Palace  ?  To  which  end  of  the  Ludwig  Strasse  is  he  to  look 
for  his  model  of  an  arch?  It  may  prove  to  be  a  useful  school;  but 
it  is  now  only  a  chaos,  and  no  master's  hand  exists  to  guide  the 
student's  mind  through  the  tortuous  mazes  of  the  unintellectual 
labyrinth  in  which  he  finds  himself  involved.  It  is  difficult  to  im- 
agine in  what  direction  the  tide  may  ultimately  turn.  If  the  Ger- 
man mind  is  capable  of  originality  in  Art,  it  ought  to  be  for  good. 
They  have  copied  everything,  and  exhausted  themselves  with  imi- 
tations ad  nauseam.  It  remains  to  be  seen  whether  they  can  now 
create  any  worthy  of  admiration." 

The  view  here  reproduced  shows  not  only  the  bridge  over  the 
Iser  River,  but  gives  a  very  good  idea  of  the  magnificence  of  the 
buildings  of  the  city,  as  represented  by  the  Maximilianeum. 

Attention  will  only  need  to  be  drawn  to  the  details  of  the  bridge, 
which  are  of  the  richest  character.  The  arch  ring  is  highly  molded 
on  the  intrados  and  on  the  extrados.  The  Keystone  of  each  span, 
highly  carved,  is  capped  and  becomes  a  console  under  a  post  of 
the  parapet  railing  at  the  center  of  the  span,  while  similar  posts 
over  the  piers,  carrying  lamp  posts,  are  supported  by  caps  on  coun- 
terforts. The  railing  itself  is  in  panels,  with  turned  balusters  and 
molded  capping.  The  brick  spandrels  are  decorated  with  royal 
insignia. 


MOSELLE   BRIDGE. 

THE  town  of  Coblenz,  at  the  junction  of  the  Moselle  and  the 
Rhine,  was  founded  by  the  Romans.     Aurelian  rebuilt  the 
great  military  road  about  the  year  270,  and  remains  of  the 
pile  bridge  over  the  Moselle  were  discovered  in  1864,  just  below 
the  present  bridge. 

The  Moselle  bridge  was  built  in  1344  by  Elector  Baldwin,  and 
was  restored  in  1440.     It  was  further  rebuilt  and  widened  in  1884. 
Hoary  with  age,  its  many  arches  in  well  nigh  perfect  preserva- 
tion, it  is  one  of  the  most  pleasing  stone  bridges  in  existence.    The 

'3 


details,  while  in  many  respects  not  of  the  most  pleasing  character, 
are  neat  and  carefully  executed.  The  cutwaters  of  the  piers  are 
plainly  capped,  and  while  neatly  pointed  against  the  spandrel  walls, 
it  was  evidently  not  realized  by  the  designer  how  much  appropriate 
counterforts  would  improve  the  appearance  of  the  structure. 

The  parapet  was  originally  of  quite  elegant  finish,  as  is  shown 
by  the  details  for  a  portion  of  the  length. 

While  studying  the  bridge  in  detail,  it  is  impossible  to  state  just 
why  the  structure  is  imposing,  but  upon  viewing  it  as  a  whole,  we 
discover  that  it  is  due  to  the  number  of  the  spans ;  the  multiplica- 
tion of  the  unit  commanding  attention,  whereas  one  single  span  by 
itself,  while  of  the  same  pleasing  outline,  would  fail  of  causing  more 
than  passing  notice. 


THE   JAREMCZE    BRIDGE 

THE  splendid  examples  of  stone  arch  bridge  construction  on 
the  line  of  the  Austrian  Street  Railways    over   the    River 
Pruth,  has  caused  the  insertion  of  a  description  of  them 
in  this  part  of  the  Studies,  which  would  otherwise  have  been  de- 
voted exclusively  to  German  Stone  Arches. 

The  primary  reason  for  their  construction  was  due  to  the  fact 
that  they  would  prove  cheaper  than  steel  bridges  in  such  locations 
as  were  afforded  by  the  narrow  and  deep  valley  of  the  Pruth. 

The  bridge  at  Jaremcze  has  the  largest  span  of  the  four  struc- 
tures, all  of  which  have  long  spans  over  the  river,  with  one  or  more 
short  approach  spans  on  each  side  as  shown  in  the  view.  At 
Worochta  there  are  two  crossings,  one  with  a  main  span  of  113.5 
feet,  and  another  with  a  main  span  of  131.2  feet;  at  Jamma  the  main 
span  is  157.4  feet;  while  at  Jaremcze  the  main  span  is  213  feet  long, 
or  at  the  time  it  was  built  the  second  largest  stone  span  in  existence, 
and  since  the  completion  of  the  Luxembourg  bridge  the  third  larg- 
est. The  rise  is  59  feet,  the  thickness  of  the  arch  ring  at  the  spring 
is  10.2  feet  and  at  the  crown  6.9  feet,  with  a  width  of  only 
14.7  feet,  or  just  enough  for  a  single  track  railway.  This  narrow 
width  is  the  one  feature  of  the  design  most  open  to  criticism.  The 
arch  itself  has  enough  rise  to  give  it  a  bold  effect,  which  is  height- 
ened and  made  pleasing  by  the  arched  spandrels,  a  mode  of  con- 
struction which  Edwards  learned  was  necessary  by  experimenting 
in  building  the  Pont-y-Pryd  bridge,  but  which  he  executed  in  a  less 
happy  manner,  using  circular  openings  to  lessen  the  weight  over 
the  haunches.  The  arch  ring  has  well  defined  and  exposed  skew 
backs,  and  is  constructed  of  cut  stone,  laid  in  mortar  composed  of 
one  part  Portland  cement  and  three  and  one-half  parts  of  sand. 
The  spandrel  arches  have  a  span  of  11.8  feet,  while  the  short  ap- 
proach spans  are  26.2  feet  and  the  longer  ones  39.4  feet. 

No  particular  effort  seems  to  have  been  made  for  architectural 
embellishment,  entire  reliance  having  been  placed  on  the  simplicity 
and  boldness  of  the  design,  but  it  is  to  be  regretted  that  a  coping 
or  cornice  was  not  added  to  finish  the  structure. 

Ludwig  Huss,  the  chief  engineer,  has  stated  that  these  arches  of 

14 


such  length  would  not  have  been  constructed,  except  for  the  satis- 
factory results  of  a  series  of  experiments  conducted  by  a -commit- 
tee on  arches  of  the  Austrian  Society  of  Engineers  and  Architects, 
even  in  the  face  of  the  existing  Cabin  John  arch  of  220  feet  and  the 
Grosvenor  arch  of  200  feet  span. 

The  Jaremcze  bridge  is  approximately  600  feet  long  and  cost 
$33,890;  the  Jamma  bridge  is  approximately  400  feet  long  and  cost 
$18,870;  while  the  Worochta  bridges  are  approximately  409  feet 
and  700  feet  long,  and  cost  $14,630  and  $16,430  respectively. 

While  these  lengths  are  approximate,  they  will  serve  for  the  pur- 
pose of  comparison,  the  low  cost  of  the  longest  of  the  Worochta 
bridges  being  due  to  the  short  river  span  and  the  preponderance  of 
approaches. 


THE   SCHLOSS    BRIDGE. 

THE  details  of  the  stone  bridges  of  Berlin  are  generally  such 
as  one  would  expect  where  they  are  surrounded  by  so 
much  architectural  magnificence.  The  Museum  in  the 
background,  being  of  classic  design,  naturally  calls  for  details  of  a 
chaste  description  in  the  Schloss  bridge.  The  piers,  with  rounded 
ends,  are  neatly  capped,  and  with  the  masonry  abutments  of  the 
center  openings,  are  sufficiently  heavy  to  give  every  appearance  of 
stability  with  the  flat  side  arches  which  exert  such  direct  horizontal 
thrust.  The  arch  stones  run  through  to  the  cornice  except  in  the 
case  of  the  last  few  on  each  side,  which  joggle  into  the  spandrel 
courses.  A  bridge  of  this  character,  however,  serves  mainly  to 
carry  the  street  over  the  stream,  a  fact  which  is  evidenced  by  the 
parapets.  The  railings  are  of  very  elaborate  and  ornate  design, 
while  over  each  pier  and  abutment  are  pedestals,  supporting  stat- 
uary of  great  artistic  beauty.  The  open  space  on  either  side  of  the 
street  afforded  by  the  bridge,  opens  UD  a  vista  which  is  properly 
introduced  by  such  ornamentation,  being  reinforced  by  the  notable 
buildings  which  are  brought  to  view. 


HEIDELBERG  BRIDGE. 

HEIDELBERG,  situated  on  the  left  bank  of  the  Neckar  River, 
is  a  town  mainly  of  one  street,  and  is  famous  for  its  Castle 
and  University. 

Heidelberg  University  was  founded  in  1386,  is  the  third  oldest  in 
Germany,  and  as  the  cradle  of  science  in  South  Germany,  is  also  one 
of  the  most  famous  seats  of  learning  in  the  world.  To  engineers  this 
lends  an  especial  charm  to  the  old  bridge  over  the  Neckar,  which 
in  its  mediaeval  character  is  quite  in  harmony  with  the  University 
and  the  Castle. 

Owing  to  the  broken  line  of  the  roadway  and  the  crudeness  of 
the  details,  it  is  lacking  in  beauty,  but  is  nevertheless  an  imposing 
structure. 

15 


It  was  built  in  1788  by  the  Elector  Charles  Theodore,  whose 
statue  is  seen  on  the  pier  retreat  at  the  extreme  right  of  the  viewr. 

The  statue  of  Minerva,  on  the  pier  near  the  center,  adds  very 
much  to  the  dignity  of  the  entire  bridge.  Over  the  other  piers  are 
retreats  on  brackets,  which  relieve  the  otherwise  flat  appearance  of 
the  bridge. 

The  springing  of  the  arches  is  concealed,  the  masonry  work  is 
not  first-class,  the  arch  stones  being  uneven  both  in  thickness  and 
length,  but  the  coping  or  cornice  is  an  admirable  detail,  even 
though  the  effect  is  spoiled  bv  the  iron  railing  which  guards  the 
roadway. 

With  all  the  faults  named,  and  many  others  not  mentioned,  the 
grandeur  and  dignity  of  the  ensemble  must  not  be  forgotten. 


THE    FRIEDRICHSBRUCKE,   BERLIN. 

THERE  are  so  many  works  of  architecture  in  Berlin  worthy 
of  description,  that  attention  is  seldom  called  to  the  designs 
of  the  bridges, yet  in  the  Friedrichsbrucke  there  is  an  exam- 
ple of  stone  bridge  architecture  that  will  repay  a  great  deal  of 
study. 

Beginning  with  the  piers,  the  courses  of  stone  are  accentuated 
by  the  chamfered  joints,  while  there  is  both  a  coping  or  cornice 
and  a  cap  to  finish  them,  and  counterforts  are  used  above  to  divide 
the  spandrels  of  adjacent  spans  and  relieve  the  flat  surface. 

The  skewbacks  of  the  arches  are  exposed,  which  should  always 
IK-  the  case,  and  the  arch  ring  is  full  at  the  springing,  although 
beautifully  molded  beyond  ;  a  detail  which  could  not  well  be  omitted 
with  such  surroundings,  although  to  be  avoided  in  large  arches. 

Upon  a  coping  of  plain  design,  which  gives  proper  relief  to  the 
smooth  spandrels,  is  a  parapet  of  very  simple  design,  yet  having  a 
very  rich  effect. 

Bracketed  over  the  piers  are  elaborate  pedestals  carrying 
statues,  holding  aloft  torch-shaped  lamp  globes ;  bringing  out  very 
strongly  the  appropriateness  of  ornamental  supports  for  our  street 
lights.  While  at  first  glance  it  may  seem  that  the  bridge  is  made 
to  appear  much  more  ornate  than  it  really  is  by  the  magnificence 
of  the  buildings  beyond,  yet  upon  careful  study  we  must  concede 
that  this  bridge  is  one  of  the  best  designed  stone  arch  structures 
to  be  found  anvwhere. 


16 


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